Advanced: Caching

browser.cache.disk.enable
(Boolean). When set to true (Default), this enables
Firefox to cache data to the hard drive (This can be further tuned by
options covered beneath). Theres no need to disable (false)
this; if you dont wish to store the browser cache on the hard drive when
not required, the Clear Private Data utility (Covered earlier) allows
you to automatically delete it.

browser.cache.disk.parent_directory
(String). This entry allows you to specify a location for the cache
directory (The default location will be in the Profiles
directory). If entering this location in about:config use the
standard path format, e.g. C:\Windows\Temp, whereas if entering this
into the User.js file via text editor double\ are
required in the path, e.g. C:\\Windows\\Temp.

browser.cache.disk_cache_ssl
(Boolean). When set to false secure webpages (https://, etc.)
are not saved in the cache folder. This is quite sensible from a security
point of view (Although may many certain sites are slower to navigate
compared to other Browser, which may cache secure content by default
 such as Internet Explorer), as you dont really want secure data
cached on your hard drive. Unless you have a specific reason to enable
(true) this, leave it set to false.

browser.cache.disk.capacity
(Integer). The value entered here specifies the size, in KB, of the
browsers hard drive cache. This improves the rendering speed of a webpage
as data (images, etc.) can be loaded directly from the hard drive as opposed
to needing to be downloaded. On the negative side, this can potentially mean
old data is loaded rather than newer versions, which can be countered with
the browser.cache.check_doc_frequency setting. Several dozen MBs
(With 1024KB = 1MB) should prove sufficient for the browser cache, theres
no need to go excessive with it (Though if you browse a lot of sites daily
then it may be more worthwhile). Personally I use 51200 (50MB).

browser.cache.check_doc_frequency
(Integer). The value entered specifies how often never versions of
cached files are check for. 0 checks once per session. 1
checks each time the webpage is loaded. 2 specifies that the cached
version is used if it exists. While 3 checks automatically (Whenever
its out of date).

browser.cache.memory.enable
(Boolean). When set to true, this enables Firefox to
cache data into RAM (This cache is not equivalent to the hard drive cache
and only stores images and chrome). The benefit of this is that RAM is much faster
than the hard drive so loading of cached data should be further improved
(Highly useful during Back/Forward operations). Memory usage is determined
by what Firefox needs, i.e. viewing multiple image intensive
windows/tabs RAM usage will be high. If you dont wish waste RAM caching
browser data (More of a concern where you are dealing with image intensive
pages) then set this to false.

browser.cache.memory.capacity
(Integer). This
preference does not control how much RAM may be used by Firefoxs
memory cache; rather it sets the amount of RAM, in KB, which Firefox will
attempt to reduce memory usage to whenever possible, e.g. after closing
windows/tabs. In the address bar enter (Or copy and paste) about:cache
to view memory cache info;

Memory cache device

Number of entries:

410

Maximum storage size:

18432 KiB

Storage in use:

10871 KiB

Inactive storage:

8011 KiB

When set to -1 Firefox determines this value
based on
RAM installed as indicated
in the table beneath;

RAM (MB)

Memory Cache (KB)

32

2048

64

4096

128

6144

256

10240

512

14336

1024

18432

2048

24576

4096

30720

Again, understand that Firefox will exceed this value
as necessary; the value entered more so relates to how aggressively
Firefox attempts to free cached data from RAM. Personally speaking youre
probably best off setting to -1 rather than specifying an actual
value.

browser.sessionhistory.max_total_viewers
(Integer). This
value specifies the number of content viewers cached for faster
(instantaneous) Back/Forward operations. The default is -1,
which calculates the amount based on
RAM installed. Should you
encounter problems with memory use (Or other issues) with this enabled,
set it to 0 to disable it, although Back/Forward operations
will be slower as a result.

browser.sessionhistory.max_entries
(Integer). The value entered here specifies the maximum number
of history entries displayed for Back/Forwards operations, the default
being 50. Note, this has no effect on the number of entries stored in
History itself, merely how many are available for Back/Forwards operations
in a window. Theres no real need to change this value, but if you must,
alter it to a value based on how many pages youre likely to view
consecutively in 1 window &/or by how many pages youre likely to skip
back/forwards in such cases (More than likely itll be less than the
default). Personally I use 10.

config.trim_on_minimize
(Boolean). Setting this to true specifies that Firefoxs
working set can be trimmed when minimized; freeing RAM for use by other
processes (See
here for further information). This is common
practice for applications, although as discussed in
Bug 76831, Firefox can
temporarily become unresponsive when attempting to bring it to the
foreground again (Though performance is fine once it has been),
unfortunately this is compounded by multiple other memory related bugs in
Firefox. As such you might find it best to set this to false to
disable such swapping (Thereby avoiding the responsiveness issues).
Alternatively, if you dont intend to use Firefox for some time, simply
close it instead.

network.cookie.lifetimePolicy (Integer).
This option allows you to control how cookie storage is handled. 4 options
are available (Note  This is the similar to the Accept cookies from
sites  Keep until option in the Privacy tab, albeit features an
additional option).

0. This specifies
that cookies are stored until they expire, as per their expiration date.
This can vary greatly from site to site (and for what purpose). In my own
case, of 3 cookies the expiration dates were 2006, 2010 and 2037. As a result,
selecting 0 is most likely to lead to a whole heap of cookies stored
on your PC until either you use the Clear button or start deleting them
manually. That said, this option also ought to provide the most hassle free
mode of operation.

1. Selecting this
option prompts you with the beneath whenever accepting a cookie is
concerned.

●
Use my choice for all cookies from
this site. Selecting this option sets
Firefox to apply the option chosen (Allow/Allow for Session/Deny) for all
further cookies originating from the site in question. This would be
recommended where you would visit a website regularly or incidentally
receive a lot of prompts regarding their cookies and wish to specify how to
handle all their cookies.

●
Show/Hide Details.
Clicking this button allows you to view/hide details on the cookie that
confirmation is currently being prompted for. This may help you decide
whether to accept/deny it.

●
Allow.
Select this button to enable the creation of a cookie from the site.
This would be recommended where the cookie is benign in function, e.g. for
storing forum login details so you wont need to login every time.

●
Allow for session.
Select this button to enable the creation of a cookie from the site,
but which lasts only for the current Firefox session.

●
Deny.
Select this button to disable the creation of a cookie from the site.

2. Selecting this
option allows cookies to be accepted without prompting you, albeit only
until the Firefox session is closed. This offers a decent trade-off between
convenience and privacy/cluttering. As you may have realised from earlier
though, downsides can include things such as having to re-entering login
information for sites each time you wish to enter them.

3. This option
specifies that accepted cookies expire after the number of days set by
network.cookie.lifetime.days. This can be useful as many cookies can
set expiration dates days, weeks, even years into the future, this
allows for some longevity for such cookies, without allowing your system
retain them for too long.

network.cookie.lifetime.days (Integer).
When network.cookie.lifetimePolicy is set to 3, this option
specifies how long, in days, a cookie is stored before expiration (Ignoring
the expiration date of the cookie if longer than whats set), the default
being 90 days. Increase or decrease this as you see
fit, personally Id use 7 days.